I own Cyber 800 for about a year and I'm very happy with them . I got them from a N.J show room of "Quest for Sound" . I talk to Steve (owner of the store & dealer for Opera Audio line) before the show about these amp. but simply could not commit financially. At the end of the show he gave me an offer I couldn't resist. After getting home I set them up with my Martin Logans Aerius I & listen. I was very impressed what I was hearing. The vocal were cleaner more redefine , stage was deeper with more layers then before. Bass was punchier & over all more musical in the same time. Sound became more like real music (isn't it what we all want). My McIntosh witch I used before simply could not keep up with Cybers. Recently I replace original tubes with NOS tubes from Amperex 6922 white label made in Holland(1960)& Tungsol 5687 from early 1960's , also replaced stock EL34 with JJ blue new line. After installing new tubes sound became more sweeter , even better sound stage then before , very tree dimensional and better resolucion . About two months ago I purchase Vandersteen Quatro witch in my humble opinion are the best speakers for the money (I was also looking at Opera M-15 but they are to big for my New York apartment). I was a little concern about Cyber 800 driving new speakers at first , because they are only 78 watts per channel. My worries quickly disappear . Cybers had no problems driving Vandys. The 300 watts amp. ( driving bass units ) build in Vandys properly helped. If you are looking for natural, musical and universal amp( accepts EL34,KT88 and 6550's witch will bring it to 110 watts per channel ) look no farther. Take my word for it. You will save a large amount of money & you will be happy for a long time.

I'm sorry for confusion about other tubes that I said can be used with cyber 800. I personally did not try it. I got this information from one of the papers Steve from "Quest for Sound" gave me when I purchase these amps. If in fact these tubes can not be used with Cyber 800 amps. I will contact Steve & ask him for clarificacion. If those brochures give misleading information they should be removed immediately from his shop display section. Ones again I apologize for any confusion this may cost. Sincerely M.Stark

I just don't want anyone ending up with a 4th of July scenario. I have personally tried the JJ KT77, Sovtek 6550, EH KT88, and JJ KT88 in the Cyber 800 tube monoblock amplifiers. None are compatible due to the bias settings. It will be apparent within about 5 to 7 seconds this isn't something that's going to work.

All of the EL34 and 6CA7 I have tried have no issue.

The Cyber 800 uses a cathode bias configuration. While you cannot run the other tube types, it's quite convenient in that there is nothing to adjust.

Joe. Thank You for clarification. P.S I did not know that Steve isn't a OPERA dealer any more ( have not talk to him in a while ). I'm very surprise , because Consonance was probably one of his most successful lines. Anyway, thanks again. Sincerely ; M.Stark

Some of the other Cyber amplifiers actually are manual bias. In fact, because of this feature, which I consider a convenience, I have modified my own Cyber 211 amplifiers to be able to run both 211 and 845 output tubes without having to perform any of the usually required surgery. Flip the switch, change tubes, rebias, DONE.

The 211 is more open, detailed, and forward, possesing that midrange magic. The 845 is more romantic and full-bodied, with a lot more in the way of low frequencies. They make for a far more disparate sound than I would have ever expected. I like the fact of being able to change so easily from one to the other to suit my mood, music, ancillary components, etc. I could never do this if the amps were autobias.

Dear Trejla.I agree with you a 100% about magical midrange & phenomenal ability to reproduce vocals of Cyber 211. Choosing Cybers 800 was a difficult decision which was base on two factors.1. Motivating reason for purchasing 800s was significant discount ( SHOW demo pair ).2. I like they ability of reproducing different kinds of music equally well. In my opinion they didn't have any significant weaknesses but I have to admit that they didn't shine in any particular area neither. In general a very universal amp. That was exactly what I was looking for.Now going back to your last post. Your idea of modifying 211 & making them comparable with 845 tubes sounds very interesting and tempting in the same time. Trelja can you help me out with some questions regarding your modificacion and my speakers?1. I love jazz & blues but I also like to ROCK the house sometimes. That's one of the reasons I choose Cyber 800. Do you think that 211-modify will rock my boat or only classic, jazz, small band & acoustic recordings would benefit from this mod?2.Vandersreen Quatros sensitivity is: 87dB - do you think 211 will have enough power and authority to drive them ( I'm a little sceptic to be honest )?3.If the answer is yes can this upgrade be provided with possibility of a trade in?Sincerely M.Stark

M. Stark, thank you for your inquiry! Here are my answers to your questions:1) Without a back-loaded horn type speaker, none of the 211, 845, or 300B variants can rock out like the Cyber 800. With a more traditional dynamic speaker, the Cyber 800 is the powerhouse of the group, no question.

That being said, with the right loudspeaker, you can do pretty well. I usually listen at 90 dB+, and my favorite amplifiers of the bunch are the Cyber 300B PSE, they have a level of refinement and delicacy unmatched by most any other amplifiers I've heard. Interestingly enough, they seem to mate best with traditional speakers. I like the 211 best with back-loaded horns (using Lowther type drivers) such as Lamhorns, etc., and the 845 seems to do the best with front loaded horns like the Consonance M15)

2) You and I are of the same mind. The only way to really answer the question is to try the combination. If you have the speakers, I'm willing to supply the amps so that we can give them a go

3) The short answer is that we can probably work something out for you

ps - I'm going away for a few days to the New Jersey shore, and if I do not respond to further inquiries, please accept my apologies in advance.